Tap changing apparatus



TAP CHANGING APPARATUS 2 Sheets-Sheet 1 Filed De'c. 8, 1958 now own

Nov. 27, 1962 R. D. FANNON, JR., ETAL 3,066,208

TAP CHANGING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 8, 1958 uOo WWM. 8m W Vww m 5 w E m m m 29 8 u 1! 3m 2w 3m ATTORNEYS hired 3,056,2il8 Patented Nov. 27, 19%2 3,066,208 TAP CHANGING APPARATUS Robert D. Fannon, .lra, Columbus, and Harold J. Behm,

Canal Winchester, Ghio, assignors. by mesne assignments, to Wagner Electric Corporation, St. Louis, Mo.,

a corporation oE Deiaware Filed Dec. 8, 1958. Ser. No. 778,796 17 Glaims. (Cl. 20ti153) This invention relates to tap changing apparatus. It includes improved simplified tap selecting switching means and associated driving mechanism.

Tap changing apparatus according to this invention includes tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with the tap-selector stationary contacts; means for moving the tapselcctor movable contacts into and out of contact with the tap-selector stationary contacts selectively to provide at a given time either electrical contact between both tapsclector movable contacts and one tap-selector stationary contact or between the first tap-selector movable contact and one tap-selector stationary contact and between the second tap-selector movable contact and the next adiacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to the first tapselector movable contact; a second load-transfer stationary contact electrically connected to the second tapselector movable contact; first and second load-transfer movable contacts associated with the load-transfer stationary contacts; load conductor means electrically connected to both load-transfer movable contacts; and means for moving the load-transfer movable contacts into and out of contact with the loadtransfcr stationary contacts selectively to provide at a given time either electrical contact betwee both load-transfer movable contacts and one load-transfer stationary contact or between the first load-transfer movable contact and one load-transfer stationary contact and between the second load-transfer movable contact and the other load-transfer stationary contact.

The invention includes means for switching the load conductor means from electrical connection with only one tap to electrical connection with the one tap and the next adjacent tap comprising, means for (1) moving the load-transfer movable contacts from a first load-transfer position wherein the first load-transfer movable contact is in contact with the first load-transfer stationary contact and the second load-transfer movable contact is in co tact with the second load-transfer stationary contact to a second load-transfer position wherein the first load-transfer movable contact remains in contact with the first loadtranster stationary contact and the second load-transfer movable contact also makes contact with the first loadtransfer stationary contact, (2) then moving the tap-selcctor movable contacts from a tap-selector position wherein the first and second tap-selector movable contacts are both in contact with one tap-selector stationary contact to a tap-selector position wherein the first tap-selector movable contact remains in contact with the one tapsclector stationary contact and and the second tap-selector movable contact makes contact with the next adjacent tap-selector stationary contact, and (3) then moving the load-transfer movable contacts from the second loadtransfer position to a third load-transfer position wherein the second loadtranster movable contact remains in contact with the first load-transfer stationary contact and the first load-transfer movable contact makes contact with the second load-transfer stationary contact.

The invention also includes means for switching the load conductor means from electrical connection with two adjacent taps to electrical connection with only one of the adjacent taps comprising, means for (1) moving the load-transfer movable contacts from a first load-transfer position wherein the first load-transfer movable contact is in contact with the second load-transfer stationary contact and the second load-trrnsier movable contact is in contact with the first load-transfer stationary contact to a second lcadtrsnster position wherein the first load-transfer movable contact remains in contact with the second load-transfer static-nary contact and the second load-transfer movable contact also makes contact with the second load-transfer stationary contact, (2) then moving the tapselector movable contacts from a tap-selector position wherein the first tapse1ector movable contact is in contact with a first tap-selector stationary contact and the second tap-selector movable contact is in contact with a second tsp-selector stationary contact, adjacent to the first tapselector stationary contact, to a tap-selector position wherein the second tapselector movable contact remains in contact with the second tap-selector stationary contact and the first tap-selector movable contact also makes contact with the second tap-selector stationary contact, and (3) then moving the load-transfer movable contacts from the second load-transfer position to a third load-transfer position wherein the second load-transfer movable contact remains in contact with the second load-transfer stationary contact and the first load-transfer movable contact makes contact with the first load-transfer stationary contact.

The invention further includes means for switching the load conductor means from electrical connection with one tap to electrical connection with the next adjacent tap, and means for switching the load conductor means from electrical connection with first and second adjacent taps to electrical connection with the second tap and a third tap adjacent to the second tap on the side of the second tap opposite to the first tap. These means comprise combinations of the means described in the two preceding paragraphs, for providing the three movements of contacts as des ribed in one paragraph and then the three movements of contacts as described in the other paragraph, the final position of the load-transfer movable contacts after all six movements being the same as the first position of these contacts.

in a preferred form of the invention, the means for moving the load-transfer movable contacts and the means for moving the tap-selector movable contacts include a first Geneva gear drivingly connected to the load-transfer movable contacts, a second Geneva gear drivingly connected to the tap-selector movable contacts and a Geneva driving member comp ising means for driving the first Geneva gear and means for driving the second Geneva gear. The Geneva driving member preferably comprises means for (l) rotating said first Geneva gear through a first predetermined angle, (2) then rot Ling said second Geneva gear through a second predetermined angle, and (3) then further rotating said first Geneva gear through said first predetermined angle, (4) then still further rotating said first Geneva gear through said first predetermined angle, (5 then further rotating said second Geneva gear through said second predetermined ang e, and (6) then still further rotating said first Geneva gear through said first predetermined angle, preferably including a pinion engageable with the second Geneva gear and a pair of pinions engagcable with the first Geneva gear.

The second Geneva gear preferably is located in a plane parallel to the plane of the first Geneva gear, and the Geneva driving member is rotatable in both directions and comprises a first pinion located in the plane of, and engageable with, the second Geneva gear and second and third pinions, preferably spaced at an angle of less than 189, and located in the plane of, and engageable with, the first Geneva gear. Where the Geneva driving member is rotatable about an axis located between the axes of the first and second Geneva gears, the second and third pinions may be spaced symmetrically on either side of the first pinion, each at an acute angle from the first pinion.

Mechanical features of the invention include apparatus for providing rotary movement of first and second parallel shafts in a predetermined sequence comprising in combination: a first Geneva gear connected to the first shaft; 2. second Geneva gear connected to the second shaft in a plane spaced from the plane of the first Geneva gear; and a Geneva driving member, preferably rotatable in both directions, comprising a first pinion located in the plane of, and engageable with, the second Geneva gear and second and third pinions preferably spaced at an angle of less than 180, and located in the plane of, and engageable with, the first Geneva gear. Where the Geneva driving member is rotatable about an axis located between the axes of the first and second Geneva gears, the second and third pinions may be spaced symmetrically on either side of the first pinion, each at an acute angle from the first pinion. The apparatus is useful for (l) rotating a first shaft through a first predetermined angle, (2) then rotating a second shaft, located parallel to the first shaft, through a second predetermined angle, and (3) then further rotating the first shaft through the first predetermined angle.

In the drawings:

FIG. 1 is a simplified elevational view of a switching mechanism according to the present invention together with a schematic diagram of associated wiring;

FIG. 2 is a simplified elevational view of a transmission mechanism according to the present invention for driving the switching mechanism of FIG. 1;

FIG. 3' is an enlarged sectional view, partially revolved and with parts cut away, taken on the plane 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken on the plane 4-4 of FIG. 3;

FIGS. 5, 6, 7, 8, 9, 10, and 11 are diagrammatical views of the switching mechanism of this invention in various positions, illustrating certain operations of the invention.

Switches Referring to FIG. 1, panel Zti made of strong insulating material supports a load-transfer switch 21, a tapselector switch 22, and a reversing switch 23. The loadtransfer switch 21 includes stationary contacts 24a, 24b, and movable contacts 25a, 25b. The movable contacts 25a, 251; are fixedly attached by an electrically conductive mounting assembly as to a rotatable shaft 2'7 made of strong insulating material. The movable contacts 25a, 2512 are electrically connected through a spring-loaded wiper contact 23 to a collector ring 29, which is coaxial with the shaft 27. The collector ring 29 is connected by a conductor 36 to a load 43. The stationary contacts 24a, 24b are arcuate in shape, and are oppositely disposed about the shaft 27 and coaxial therewith. Each stationary contact 24a, 24b preferably extends over an are greater than 90 and less than 18f). The movable contacts 25a, 25b extend radially from the shaft 27 at approximately 90 from each other.

The shaft 27 may be rotated in either direction to position the movable contacts 25a, 25b selectively in the lower position shown in FIGS. 1, 5, and 11 with the movable contact 25a coniacting the stationary contact 24a and with the movable contact 25b contacting the stationary contact 24b; in a left-hand position shown in FIGS. 6 and 7 with both of the movable conacts 25a, 25b contacting the left-hand stationary contact 24a; in an upper position shown in FIG. 8 with the movable contact 25a contacting the stationary contact 24b and with the movable contact 25b contacting the statirnary contact 24a; or in a right-hand position shown in FIGS. 9 and with both of the movable contacts a, 25b contacting the right-hand stationary contact 2412.

The tap-selector switch 22 includes 9 stationary contacts 31a, 31b, 31c, 31d, 31e, 31f 31g, 31h and 311, and a pair of movable contacts 32a, 32b. The movable contacts 32a, 32b are rigidly attached by a mounting assembly 33 to a shaft 34 made of strong insulatng material. The mounting assembly 33 includes conductive members 35 connected to the movable contact 32a and providing spring loaded wiping contact, as indicated at 36, to an inner collector ring 37, which is coaxial with the shaft 34. The mounting assembly 33 a'so includes conductive members 33 connected to the movable contact 3212 and providing spring-loaded wiping contact, as indicated at 39, with an outer collector ring 40, which is coaxial with the shaft 34. The mouning assembly 33 also includes an insulator member 41 between the conductive members 35', 38 and fixedly attached to both of the members 35, 38.

The stationary contacts 31a3li are poitioned around a circle concentric with the shaft 34 and equally spared apart. The circumferential width of each stationary contact 31a-3li is greater than the spacing between successive contacts, and the spacing between the movable contacts 32a, 32b is greater than the spacing between successive stationary contacts 31a-3li but not greater than the width of each stationary contact 3la-3lz'. Thus both of the movable contacts 32a, 32b can contact a single stationary ccntact 3161-311 as shoWn in FIGS. 1, 5, 6, 10, and 11, and the movable contacts 32a, 32b can be positioned in intermediate locations such that the movable contact 32a contacts one of the stationary contacts 31:1-311' and the movable contact 32b contacts the next stationary contact 31b31a as indicated in FIGS. 7, 8, and 9 which show the movable contact 32a contacting the stationary contact 31g and the movable contact 32b contacting the stationary contact 31h. The Shaft 34 may be rotated in either direction.

The reversing switch 23 includes a pair of stationary contacts 46a, 46b and a pair of movable contacts 47a, 47b. The movable contacts 47a, 47b are electrically connected together and rigidly connected mechanicaly by a conductive mounting assembly 48 to a pivotable shaft 49 made of strong insulating material. The stationary contacts 46a, 46b are positioned as shown, equidistant from the shaft 49 and spaced such that with the movable contacts 47a, 47b in the position shown in FIG. 1 the movable contact 47a contacts the stationary contact 46a and the movable contact 47b contacts the right end of the stationary contact 31a of the tap-selector switch 22; and when the shaft 49 is pivoted clockwise through a small angle the movable contact 47a moves into contact with the stationary contact 461) and the movable contact 4712 still contacts the stationary contact 31a at the left end of the stationary contact 31a of the tap-selector switch 22.

The stationary contact 24a of the load-transfer switch 21 is connected, preferably through an inductive reactor 50, to the inner collector ring 37, and thus to the movable contact 32a of the tap-selectorswitch 22-. The stationary contact 2412 of the load transfer switch 21 is connected, preferably through an inductive reactor 51, to the outer collectcr ring 4t and thus to the movable contact 32b of the tap-selector switch 22. The stationary contact 31a of the tap-selector switch 22 is connected to one end of a power transformer winding 52, the other end of which is connected to the load 43. The stationary contact 46a of the reversing switch 23 is connected to one end of another power transformer winding 53, which is inductively coupled to the winding 52 The stationary contact 4622 of the reversing switch 23 is connected to the opposite end cf the winding 53. The stationary contact 310-311' are connected respectively to taps 58b-53i of the winding 53.

With all of the switches in the positions shown in FIG. 1, the load is connected directly to the winding 52. With the switches in other positions, the load 43 shown in FIG. 1.

.aoeaaos may be connected across the winding 52 and at least one part of the winding 53 such that the voltage supplied to the load 43 is a desired amount greater or less than the voltage across winding 52 depending upon the position of the reversing switch 23, which ccnn:cts the winding 53 selectively either in phase, or 180 out of phase, with the Winding 52.

Transmission Referring to FIG. 2, a transmission assembly 69 is mounted on the opposite side of a panel 26a parzllel to and registering with the insulating pawl 21?. The transmission assembly includes a load-transfer Geneva gear 61 rigidly connected to the shaft 27, a tap selector Geneva gear 62 rigidly connected to the shaft 34, a re versing switch linkage 63 rigidly connected to the shaft 49, and a Geneva driving member 64 rigidly connected to a driving shaft 65. Any suitable control system (not shown) may be used to rotate the driving shaft t3 rotate the shaft 65 in either direction, as desired, to provide the switching desired at any given time. The control system may be of the type that is actuated manually by an operator or of the type that is controlled by automatic means responsive to the voltage across the load 43. Many such control systems are known in the art, and the selection of a specific control system depends upon the requirements of any particular installation.

The tap-selector Geneva gear 62 is an l8-slot Geneva gear of conventional shape, as shown in FIG. 2, and includes a cam 66 formed by an inner circular slot 67 extending approximately 320 and an outer circular slot 68 extending approximately 320 connected by a radial slot 69. The circular slots 67, 68 are concentric with the shaft 34. The cam 66 engages a cam follower pin 7t: rigidly connected to one end of an arm 71 in the reversing switch linkage 63. The other end of the arm 71 is rigidly connected to a sleeve 72, which is pivotably mounted on a cylindrical spindle 79 rigidly mounted on panel 29a. Also rigidly connected to the sleeve 72 is a dog 73, one end of which is pivotably linked, as indicated at 74, to one end of a reversing switch arm 75, the other end of which is rigidly connected to the shaft 49. The other end of dog 73 is connected, as indicated at 76, to one end of a tension spring 77, the other end of which is connected to a pin 73 fixedly mounted on the panel 26a.

When the tap-selector Geneva gear 62 moves counterclockwise from its position as shown in FIG. 2, the radial portion 69 of the cam 66 presses the cam-follower pin upward and thus rotates the shaft 49 through the reversing switch linkage 63 in a counterclockwise direction, as viewed in FIG. 2 (clockwise as viewed in FIG. 1), moving the reversing switch 23 from its position in FIG. 1 in which the movable contacts 47a, 47b connect the stationery contact 31a of the tap-selector switch 22 to the stationary contact 46a of the reversing switch 23, to its other position in which the connection is made to the stationary contact 465 of the reversing switch 23. The cam-follower pin 70 is moved to the outer portion 63 of the cam 66 in the course of this action. Further counterclockwise movement of the tap-selector Geneva gear 62 does not affect the reversing switch 23, as the cam-follower pin 76) remains in the same position as fixed by the outer circular slot 68 of the cam 66.

Subsequent clockwise rotation of the tap-selector Geneva gear 62 to the position where the radial slot 69 engages the cam follower 70 provides the reverse of the above action, returning the reversing switch linkage 63 to the position shown in FiG. 2 by moving the camfollower pin 70 downward and into the inner slot 67 of the cam 66, and rotating the shaft 49 clockwise as viewed in FIG. 2 (counterclockwise as viewed in FIG.

1), returning the reversing switch 23 to the position Further clockwise rotation of the ;tap-selector Geneva gear 62 does not affect the reversing switch linkage 63 or the reversing switch 23, as the camfollower pin 7t? remains in the same position as guided by the inner circular slot 67 of the cam 66. Thus, the cam 66 and the reversing switch linkage 63 provide the proper action of the reversing switch 23 to provide the usual reversing switch action required in the conventional tap-changing circuit of FIG. 1.

The loadtransfer Geneva gear 61 is a conventional 4-slot Geneva gear, as shown in FIG. 2, and is provided with a 4-position accelerator cam 80 of conventional design, which is rigidly connected to the shaft 27. Associated with the accelerator cam 89 is an accelerator arm 81, which is pivotably mounted as indicated at 82 on the panel 26 and yieldingly pressed against the accelerator cam 80 by a compression spring 83, which is held under pressure by a nut 84 on a bolt 85 fixedly attached to the panel 20a.

The Geneva driving member 64 includes a circular plate fixedly mounted on the shaft 65 and concentric therewith. A Geneva pinion 91 and a Geneva lock 92 of conventional shape are fixedly mounted on the upper face of the plate 90 for driving the tap-selector Geneva gear 62. The tap-selector Geneva pinion 91 and Geneva lock 92, of course, are located in the plane of the tape-selector Geneva gear 62, as shown in FIG. 3. Mounted below the plate 99 are a pair of load-transfer Geneva pinions 93a, 93b, and a Geneva lock 94 of conventional shape. The Geneva pinions 93a, 93b and the Geneva lock 94 are located in the plane of the loadtransfer Geneva gear 61, as shown in FIG. 3. The

inions 93a, 9312 are rigidly mounted on a wing-shaped plate 95, located just above the Geneva lock 94 and rigidly attached thereto. The Geneva lock 94 and the Wing-shaped plate 95 are rigidly attached to a sleeve 96. The three members 94, 95, 96, are described separately for convenience, but may comprise one integral member 97 for driving the load-transfer Geneva gear 61 by means of the pinions 93a, 93b.

The driving member 97 is rotatably mounted on the shaft 65 by means of bearings 98a, 98b, and is yieldingly connected to the circular plate 90' by means of six strong tension springs 99a-99f, two of which, 99a 9911, are shown in FIG. 3. One end of each spring 99a-99f is connected to a pin 10041-1007 fixedly mounted in the outer portion of the circular plate 90, and the opposite end of each spring 99a99f is connected to a pin 16111-1011 fixedly mounted in the driving member 97. The tension springs 99a99f and the pins ltltla-ltltlf, 10141-191 preferably are equally spaced around the shaft 65. The springs 9911-991 thus normally are positioned radially about the shaft 65.

The pins 101a, 161d extend upward beyond the driving member 97 into slots 102a, 1021) in the circular plate 99. The other pins 161b, 1610. 191e, 161 do not extend above the driver member 97. The slots 102a, 162k re arcuate in shape (see FIG. 4), comprising portions of a circle concentric with the shaft 65, symmetrically located on opposite sides of the shaft 65 and positioned such that the pin 101a normally is located in the middle of the slot 102a and the pin 191d is normally located in the middle of the slot 10212. The shaft 65 and the Geneva driving member 64, which comprises the components 99 192. are rotatably mounted on the panel 23a by means of a sleeve bearing 103.

The load-transfer Geneva pinions 93a, 93b are located equidistant from the shaft 65 and symmetrically about the Geneva lock 94, but they are not spaced degrees apart. With the shaft 65 located between the shaft 27 and the shaft 34-, as shown in FIG. 2, the load-transfer Geneva pinions 93a, 93b are spaced symmetrically on either side of the tap-selector Geneva pinion 91 at an acute angle from the pinion 91. Thus, the load-transfer Geneva pinions 93a, 93b are spaced at an angle of less than 180 degrees measured in the direction wh the tap-selector Geneva pinion 91 is located between the aoeeyaos pinions 93a, 93b. This arrangement provides the advantage of improved entrance angles in driving the loadtransfer Geneva gear 61 and the tap-selector Geneva gear 62 in the desired sequence by the Geneva driving member 64. Thus, both the load-transfer switch 21 and the tap-selector switch 22 are driven by a single compound driving member 64 from the driving shaft 65.

Operation of Transmission In addition to any action provided by the cam 66,

through the reversing switch linkage 63 to the reversing switch 23, as already described, one full revolution of the driving shaft 65 in a counterclockwise direction, as viewed in PEG. 2, provides the following sequence of operations.

The right-hand load-transfer Geneva pinion 93b enters the lower right-hand slot of the load-transfer Geneva gear 61 at approximately the optimum angle of 90 degrees to the Geneva gear 61 or parallel to the sides of the slot. When the pinion 93b reaches the end of the slot, further rotation of the circular plate 9% which is rigidly attached to the driving shaft 65, stretches the springs 99a99f coupling the circular plate 99 to the lower driving plate 97; since the pressure of the spring ('33 on the accelerator arm 81 is suflicient to hold the accelerator cam 89 in position by means of the roller 110 extending into the detent in the accelerator cam 8t); until the circular plate 90 moves approximately 30 degrees farther than the lower drive plate 97 and the pin 161a reaches the end of the slot 102:; and the pin ltllb reaches the end of the slot 10217. At this point the plate 99 applies positive drive to the drive plate 97 and the accelerator arm 81 must yield, allowing the roller 11%!- to move out of the detent in the accelerator cam $6. The springs 99a-99f cause the drive plate 97 to snap back to its normal position and thus catch up with the circular plate 9%. The load-transfer Geneva pinion 93b meanwhile provides a quick snap action on the load-transfer Geneva gear 61, quickly moving it one-quarter turn in the clockwise direction as viewed in FIG. 2. The new position of the load-transfer Geneva gear 61 appears the same as shown in FIG. 2 because of its symmetry.

As the load-transfer Geneva pinion 93b emerges from the slot in the load-transfer Geneva gear 61 (now in the lower left-hand position as viewed in FIG. 2), the tapselector Geneva pinion 91 enters the slot in the tapselector Geneva gear 62 that is just to the lower left of the shaft 65. Further rotation of the shaft 65 causes the pinion 91 to turn the tap-selector Geneva gear 62 through an angle of 29 degrees.

As the tap-selector Geneva pinion 91 emerges from the slot in the tap-selector Geneva gear 62 (now in the position just to the lower right of the shaft 65), the other load-transfer Geneva pinion 93a enters the slot now in the lower right-hand position on the load-transfer Geneva gear 61. Further rotation of the shaft 65 provides the same action described above in which the tension springs 99a99f are stretched and then released 'to provide a snap-action movement of the drive member 97 to rotate the load-transfer Geneva gear 61 through an additional one-quarter turn in the clockwise direction as viewed in FIG. 2. At the end of the revolution of the shaft 65, the Geneva driving member 64 returns to its original position as shown in FIG. 2. The load-transfer Geneva gear also is in the position appearing in FIG. 2, although it actually has been rotated one-half revolution in a clockwise direction. Similarly, the tap selector Geneva gear 62 has been moved approximately degrees in a clockwise direction to a position appearing the same as in FIG. 2 as far as the gear is concerned, but with the cam 66 moved approximately 20 degrees clockwise.

From symmetry, it is apparent that rotation of the driving shaft 65 through one full revolution in a clockwise direction as viewed in FIG. 2 provides the same action, only in the opposite direction, first moving the loadtransfer Geneva gear 61 through one-quarter turn in a a counterclockwise direction, then moving the tap-selector Geneva gear 62 through an angle of 20 degrees in thecounterclockwise direction, and finaily rotating the load-- transfer Geneva gear 61 an additional one-quarter turn. the counterclockwise direction, as viewed in PEG. 2. Baring the operation of the transmission 6% in either direction, and between times of operation, each Geneva lock 92, 94 prevents rotation of its associated Geneva gear 62, 61 except during the part of the revolution of the shaft 65 when the particular Geneva gear 62, 61 is being. driven by its associated Geneva pin 91, 93a, 3b.

Summarizing, one revolution of the driving shaft 65 provides one cycle of operation, comprising a -degree rotation of shaft 27, a ZO-degree rotation of the shaft 34, and then another 90-degree rotation of the shaft 27. The conventional way to provide such a sequence of rotations is to connect drive pinions to separate shafts and drive them through separate gears driven from the drive shaft. However, in the present transmission all three of the drive pinions $1, 93a, 9315 are connected directly to the driving shaft 65. This arrangement eliminates extra gearing, shafts, machining, aligning, etc.

To obtain proper timing of the mechanism, the entrance angles are slightly larger than 90 degrees, the angle that provides the best possible operation. The entrance angle is defined as the angle between lines from the centers of rotation of the Geneva pinion and the Geneva gear to the drive pin when the drive pin center just enters the slot of the Geneva gear. Decreasing the angle between the two drive pins 93a, 931) on the double drive pin member from degrees to a smaller angle from the shaft 65, with the single drive pinion 91 on the line that bisects this angle, makes it possible to obtain entrance angles closer to 9 than would otherwise be possible with the combination and arrangement of gears in FIG. 2.

Switching Operations.

Rotation of the tap-selector Geneva gear 62 through 20 degrees, as provided by a full revolution of the driving shaft 65, moves the tap-selector switch 22 from an initial position in which the movable contacts 32a, 321) both are connected to a single stationary contact 31a31i to a position in which one of the movable contacts 32a, 32b makes contact with the next stationary contact Ella-3h while the other contact 32a, 32b remains in contact with the first-mentioned stationary contact 3142-311. From an initial position in which the movable contacts 32a contacts one stationary contact 31a31i and the movable contact 321) contacts the next stationary contact 31a-3li, rotation of the tap-selector Geneva gear 62 through 20' degrees, as provided by one full revolution of the driving shaft 65, moves the tap-selector switch 22 to the next position in which both of the movable contacts 32a, 32b contact the same stationary contact fizz-311'.

With the switching elements in an initial position as shown schematically in FIG. 5, rotation of the driving shaft 65 through one full revolution, provides the following sequence of switching actions.

(1) The load-transfer switch 21 is rotated 90 degrees clockwise from the position shown in FIG. 5 with the first load-transfer movable contact 25a in contact with the first load-transfer stationary contact 24a and with the second loadtransfer movable contact 25b in contact with the second load-transfer stationary contact 24b to a second load-transfer position, as shown in FIG. 6, wherein the first load-transfer movable contact 25a remains in contact with the first load-transfer stationary contact 2411 and the second load-transfer movable contact 25b also makes contact with the first load-transfer stationary contact 24a.

(2) The tap-selector switch 22 is moved 20 degrees, causing the tap-selector movable contacts 32a, 32b to move from their initial tap-selector position, as shown in FIGS. 5 and 6, wherein the tap-selector movable contacts 32a, 3212 are both in contact with the tap-selector stationary contact 31g, to a second tap-selector position as shown in FIG. 7 wherein the tap-selector movable contact 32a remains in contact with the tap-selector stationary contact 31g and the tap-selector movable contact 321') makes contact with the next adjacent tap-selector stationary contact 3111. During this movement of the tapselector switch 22, both of the load-transfer movable contacts 25a, 251'; are disconnected from the load-transfer stationary contact 24b. Thus the load 43 is disconnected from the tapselectr movable contact 325, and there is no arcing of the contacts as the movable contact 325 moves from the stationary contact 31g to the adjacent stationary contact 3111.

(3) The load-transfer switch 21 is rotated 90 degrees further in the clockwise direction from its position as shown in FIGS. 6 and 7 to a third position, as shown in FIG. 8, wherein the load-transfer movable contact 25b remains in contact with the load-transfer stationary contact 24a and the load-transfer movable contact 25a makes contact with the load-transfer stationary contact 24]). Thus, the load 43 is connected through the condoctor 30, the collector ring 29, the wiper 23, the loadtransfer movable contacts 25a, 25b, the load-transfer stationary contacts 24a, 241), the reactors 50, 51 and the tap-selector movable contacts 32a, 32b to the tap-selector stationary contacts 31g, 31h, respectively, providing a voltage to the load 43 that is midway between the voltage provided at the tap-selector stationary contact 31g and the voltage provided at the tap-selector stationary contact 3111.

With the switching elements in the positions shown in FIG. 8, further rotation of the driving shaft 65 for one full revolution in the same direction provides the following sequence of the switching actions.

(4) The load-transfer switch 21 is rotated one-quarter turn clockwise from its position as shown in FIG. 8 to the position shown in FIG. 9 wherein the load-transfer movable contact 25a remains in contact with the load transfer stationary contact 245 and the load-transfer movable contact 252) also makes contact with the load-transfer stationary contact 2412. Thus, the load 43 is disconnected from the load-transfer stationary contact 24a and the tap-selector movable contact 32a.

The tap-selector switch 22 moves degrees further, from the position shown in FIGS. 7, 8, and 9 to the position shown in HG. 10 wherein the tap-selector movable contact 32b remains in contact with the tapselector stationary contact 31h and the tap-selector movable contact 32a also makes contact with the tap-selector stationary contact 3111. Since the tapselector movable contact 32a is disconnected from the load 43 during this switching operation, there is no arcing as it moves from the stationary contact 31g to the next stationary contact 31h.

(6) The load-transfer switch 23 is rotated clockwise one-quarter turn from the position shown in FZGS. 9 and 10 to the position shown in FIG. ll, which is its initial position as shown in FiG. 5, wherein the loadtransfer movable contact 255 remains in contact with the load-transfer stationary contact 2d]; and the load-transfer movable contact 25:: makes contact with the loadtransfer stationary contact Thus, the load as is connected through the conductor 3d, the collector ring 2?, the wiper 28, the load-transfc movable contacts 25a, 2-51), the load-transfer stationary contacts 24b, the reactors 5%, 5i, and the tap-selector movable contacts 32a, 32b to the tap-selector stationary contact 3311.

With the switching elements in the positions shown in FIG. 11, a full revolution of the driving shaft 65 in the opposite direction of course provides the reverse of the switching actions described above, moving the movable contacts from the positions shown in FIG. 11 in sequence to those shown in FIGS. 10, 9 and 8, respectively. Further rotation of the driving shaft 65' another full turn in the latter direction, with the switching elements initially in the position shown in FIG. 8, provides the switching sequence illustrated in FIGS. 7, 6, and 5, respectively. Similarly, rotation of the driving shaft for one or more full revolutions in either direction provides any desired switching of the load from an initial position connected to one tap-selector stationary contact 31a- 312' or from connection to two adjacent tap-selector stationary contacts 3la3li to any other desired position through sequences as illustrated in FIGS. 5-11 wherein the load 43 is always disconnected from one tap-selector movable contact 32a, while it is being switched from one stationary contact 31a-3li to the adjacent stationary contact Sic-31L While the form of the invention herein disclosed constitutes a preferred embodiment, there has been no attempt here to describe all of tr e possible equivalent forms or ramifications of the invention. it will be understood that the words used are words of description rather than of limitation, and that various changes may be made without departing from the spirit or scope of the invention herein disclosed.

What is claimed is:

1. Apparatus for providing rotary movement of first and second parallel shafts in a predetermined sequence comprising in combination: a first Geneva gear connected to said first shaft; a second Geneva gear connected to said second shaft in a plane spaced from the plane of saidfirst Geneva gear; and a Geneva driving member, rotatable in both directions, comprising a pinion located in the plane of, and engageable with, said second Geneva gear and pair of pinions spa ed at an angle of less than 188, and located in the plane of. and engageable with, said first Geneva gear.

2. Apparatus for providing rotary movement of first and second shafts in a predetermined sequence comprising combination: a first Geneva gear conected to said first shad; a second Geneva gear connected to said second shaft in a plane spaced from the plane of said first Geneva gee-r; 21 Geneva driving member, rotatable in both directions about an axis located between the axes of said first and second Geneva gears, comprising a first pinion located in the plane of. and engageable with, said second Geneva gear and second and third p lions spaced symmetrically on either side of first pinion, each at an acute angle from said first p on, and located in the plane of, and engageable with,

Geneva gear.

3. Apparatus for providing rotary movement of first and parallel shafts in predetermined sequence comprising in combination: a first Geneva gear connected to said first shaft; a second Geneva gear connected to said second shaft in a plane spaced from the plane of said first Geneva gear; and a Geneva driving member comprising fir t and second driving plates relatively rotatable about a common axis located between the axes of said first and second Geneva gears, spring means interconnecting said plates for concert movement and tensioned upon relative rotation of said plates, a first pinion on said first plate located in the plane of, and engageable with, said second Geneva gear, and second and third pinions on said second plate angularly spaced on opposite sides of said first pinion and located in the plane of, and engageable with, said first Geneva gear, and holding means for preventing movement of said first Geneva gear when engaged by one of said second and third pinions to effect relative rotation of said plates, said holding means permitting rotation of said first Geneva gear upon predetermined relative rotation of said plates whereby the compressive force of said spring s effects snap-action movement of said first Geneva gear.

4. Means for driving a pair of Geneva gears in a predetermined sequence comprising a pair of relatively r0- tatable driving members, angularly spaced pinions on said driving members for driving engagement with said Geneva gears, said members being concertly rotatable to drivingly engage one of said pinions with one of said Geneva gears, holding means normally engageable with said one Geneva gear to prevent movement thereof and effect relative rotation between said members, said one eneva gear being movable in opposition to said holding means upon predetermined relative rotation of said members and the other of said Geneva gears being drivingly engaged and movable by the other of said pinions subsequent to the predetermined relative rotation of said members, and a yieldable connection between said members to effect snap-action movement therebetween subsequent to the predetermined relative rotation of said members.

5. Means for driving a pair of Geneva gears positioned in spaced planes in a predetermined sequence comprising a pair of relatively rotatable members, spring means connected between said members, first and second angularly spaced pinions on said members, respectively, said members being concertly rotatable to drivingly engage said first pinion with one of said Geneva gears, and holding means for preventing movement of said one Geneva gear when drivingly engaged by said first pinion, said members being relatively rotatable to tension said spring means when said holding means prevents movement of said one Geneva gear, said one Geneva gear being movable by said first pinion in opposition to said holding means upon predetermined relative rotation of said members and the other of said Geneva gears being drivingly engaged by said secand pinion for movement subsequent to the predetermined relative rotation of said members, the compressive force of said spring means effecting a snap-action movement between said members subsequent to the predetermined relative rotation thereof.

6. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tapselector stationary contact and between said second tapselector movable contact and the next adjacent tapselector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tapelector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said loadtransfer movable contacts; means for moving said loadtransfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said loadtransfer stationary contact or between said first load-transfer movable contact and either said loadtransfer stationary contact and between said second loadtransfer movable contact and the other said load-transfer stationary contact, and means for switching said load conductor means from electrical connection with only one tap to electrical connection with said one tap and the next adjacent tap comprising, means for (1) moving said loadtransfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said first load-transfer stationary contact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second loadtransfer movable contact also makes contact with said first load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-selector position wherein said first and second tap-selector movable contacts are both in contact with one tap-selector stationary contact to a tap-selector position wherein said first tap-selector movable contact remains in contact with said one tap-selector stationary contact and said second tapselector movable contact makes contact with the next ad- }:icent tap-selector stationary contact, and (3) then mov ing said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving member comprising a pinion located in the plane of and engageable with, said second Geneva gear and a pair of pinions located in the plane of, and engageable with, said first Geneva gear.

7. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plnrality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tapselector stationary contact and between said second tapselector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said loadtransfer movable contacts; means for moving said loadtransfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable con-tact and the other said loadtransfer stationary contact, and means for switching said load conductor means from electrical connection with only one tap to electrical connection with said one tap and the next adjacent tap comprising, means for (1) moving said load-transfer movable contacts from a first loadtransfer position wherein said first load-transfer movable contact is in contact with said first load-transfer stationary contact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second load-transfer movable contact also makes contact with said first loadtransfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-selector position wher in said first and second tap-selector movable contacts are both in contact with one tap-selector stationary contact to a tap-selector position wherein said first tap-selector movable contact remains in contact with said one tap-selector stationary contact and said second tap-selector movable contact makes contact with the next adjacent tap-selector stationary contact, and (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions, comprising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair of pinions spaced at an angle of less than 180, and located in the plane of, and engageable with, said first Geneva gear.

8. In tap changing apparatus, tap selecting means cornprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second ta selector movable contact and the next adjacent tapselector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-so ector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given tin e physical and electrical contact either between both said load-transfer movable contacts and either sai load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said loadtransfer stationary contact, and means for switching said load conductor means from electrical connection with only one tap to electrical connection with said one tap and the next adjacent tap comprising, means for (l) moving said load-transfer movable cont-acts from a first loadtransfer position wherein said first load-transfer movable ontact is in contact with said first load-transfer stationary ontact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-t ansfer stationary contact and said second load-transfer movable contact also makes contact with said first load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-s lector position wherein said first and second tap-selector movable contacts are both in contact with one tap-selector stationary contact to a tap-selector pos i n wherein said first tap-selector movable contact remains in contact with said one tap-selector stationary contact and said second tap-selector movable contact makes contact with the next adjacent tap-selector stationary contact, and (3) then moving said load-transfer movable contacts from said. second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear driv ingly connected to said load-transfer movable contacts, a second Geneva gear drivingly connected to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions about an axis located between the axes of said first and second Geneva gears, comprising a first pinion loci ted in t is plane of, and engageable with, said second Geneva gear and second and third pinions spaced symmetrically on either side of said first pinion, each at an acute angle from said first pinion, and located in the plane of, and engageable with, said first Geneva gear.

9. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selectcr movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-so ector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-seiector stationary contact and between said sec- 0nd tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said loadtranster movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transier movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said loadtranst'er stationary contact; and means for switching said load conductor means from electrical connection with one tape to electrical connection with the next adjacent tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said first load-transfer stationary contact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first loadtransfer stationary contact and said second load-transfer movable contact also makes contact with said first loadtranster stationary contact, (2) then moving said [EP-SolGC- tor movable contact from a first tap-selector position wherein said first and second tap-selectormovable contacts are both in contact with a first tap-selector stationary contact to a second tapselector tron wherein said first tapselector movable contact remains in contact with said first tap-selector stationary contact and said second tapselector movable contact makes contact with a second said tap-selector stationary contact adjacent to said first tap-selector stationary contact, (3) then moving said load-transfer movable contacts from said second loadtransfer position to a third load-tansler position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; (4) then moving said load-transfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first load-transfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact a'so makes contact with said second load-transfer stationary 15 contact, (5) then moving said tap-selector movable contacts from said second tap-selector position to a third tapselector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, and (6) then moving said load-transfer movable contacts from said fourth load-transfer position to said first load-transfer position wherein said second load-transfer movable contact remains in contact with said second load-transfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and at Geneva driving member comprising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair of pinions located in the plane of, and engageable with, said first Geneva gear.

10. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector station- .ary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said loadtransfer movable contacts; means for moving said loadtransfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer stationary contact; and means for switching said load conductor means from electrical connection with one tap to electrical connection with the next adjacent tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said first loadtransfer stationary contact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second-load-transfer movable contact also makes contact with said first load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a first tap-selector position wherein said first and second tap-selector movable contacts are both in contact with a first tap-selector stationary contact to a second tap-selector position wherein said first tap-selector movable contact remains in contact with said first tap-selector stationary contact and said second tap-selector movable contact makes contact with a second said tap-selector stationary contact adjacent to said first tap-selector stationary contact, (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said first loadtransfer stationary contact and said first load-transfer movable contact makes contact with said second loadtransfer stationary contact; (4) then moving said loadtransfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first load-transfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load'transfer stationary contact, (5) then moving said tap-selector movable contacts from said second tap-selector position to a third tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, and (6) then moving said load-transfer movable contacts from said fourth load-transfer position to said first loadtransfer position wherein said second load-transfer movable contact remains in contact with said second loadtransfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions, com prising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair of pinIons spaced at an angle of less than 180, and located in the plane of, and engageable with, said first Geneva gear.

11. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first loadtransfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said loadtransfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer sttaionary contact; and means for switching said load conductor means from electrical connection with one tap to electrical connection with the next adjacent tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said first load-transfer stationary contact and said second load-transfer movable contact is in contact with said second load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second load-transfer movable contact also makes contact with said first load-transfer stationary contact, (2)

then moving said tap-selector movable contact from a first tap-selector position wherein said first and second tap-selector movable contacts are both in contact with a first tap-selector stationary contact to a second tap-selector position wherein said first tap-selector movable contact remains in contact with said first tap selector stationary contact and said second tap-selector movable contact makes contact with a second said tap-selector stationary contact adjacent to said first tap-selector stationary contact, (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second loadtransfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second loadtransfer stationary contact; (4) then moving said leadtransfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first load-transfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (5) then moving said tap-selector movable contacts from said second tap-selector position to a third tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact wtih said second tap-selector stationary contact, and (6) then moving said load-transfer movable contacts from said fourth load-transfer position to said first load-transfer position wherein said second load-transfer movable contact remains in contact with said second load-transfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear drivingly connected to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions about an axis located between the axes of said first and second Geneva gears, comprising a first pinion located in the plane of, and engageable with, said second Geneva gear and second and third pinions spaced symmetrically on either side of said first pinion, each at an acute angle from said first pinion, and located in the plane of, and engageable with, said first Geneva gear.

12. in tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tapselector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer stationary contact, and means for switching said load conductor means from electrical connection with two adjacent taps to electrical connection with only one of said adjacent taps comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said second loadtransfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first 1oad-transfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-selector position wherein said first tapselector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact with a second said tapselector stationary contacts, adjacent to said first tapselector stationary contact, to a tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, and (3) then moving said load-transfer movable contacts from said second load-transfer position to a third loadtransfer position wherein said second load-transfer movable contact remains in contact with said second loadtransfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and at Geneva driving member comprising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair of pinions located in the plane of, and engageable with, said first Geneva gear.

13. in tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tapselector movable contact; a second load-transfer stationary contact electrically connected to said second tapselector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second loadtransfer movble contact and the other said load-transfer stationary contact, and means for switching said load conductor means from electrical connection with two adjacent taps to electrical connection with only one of said adjacent taps comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first a sence load-transfer movable contact is in contact with said second load-transfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact wtih said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-selector position wherein said first tap-selector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact wtih a second said tap-selector stationary contact, adjacent to said first tap-selector stationary contact, to a tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, and (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said second loadtransfer stationary contact and said first load-transfer movable contact makes contact with said first loadtransfer stationary contact; said switching means including a first Geneva gear drivingly connected to said loadtransfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions, comprising a pinion located in the plane of, and engageable with said second Geneva gear and a pair of pinions spaced at an angle of less than 180, and located in the plane of, and engageable with, said first Geneva gear.

14. in tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary con acts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tapselector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer stationary contact, and means for switching said load conductor means from electrical connection with two adjacent taps to electrical connection with only one of said adjacent taps comprising, means for (1) moving said load-transfer movable contacts from a first load-transferposition wherein said first load-transfer movable contact is in contact with said second load-transfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a tap-selector position wherein said first tapselector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact with a second said tapselector stationary contact, adjacent to said first tap-selector stationary contact, to a tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, and 3) then moving said load-transfer movable contacts from said second load-transfer position to a third loadtransfer position wherein said second load-transfer movable contact remains in contact with said second loadtransier stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear drivingly connccted to said tap-selector movable contacts, and a Geneva driving member, rotatable in both directions about an axis located between the axes of said first and second Geneva gears, comprising a first pinion located in the plane of, and engageable with, said second Geneva gear and second and third pinions spaced symmetrically on either side of said first pinion, each at an acute angle from said first pinion, and located in the plane of, and engageable with, said first Geneva gear.

15. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tap-selector movable contact; a second load-transfer stationary contact electrically connected to said second tapselector movable contact; first and second load transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer stationary contact; and means for switching said load conductor means from electrical connection with first and second adjacent taps to electrical connection with said second tap and a third tap adjacent to said second tap on the side of said second tap opposite to said first tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said second load-transfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first load-transter movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a first tap-selector position wherein said first tap-selector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact with a second said tap-selector stationary contact, adjacent to said first tapselector stationary contact, to a second tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said second loadtransfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; (4) then moving said load-transfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first loadtransfer movable contact remains in contact with said first load-transfer stationary contact and said second loadtransrer movable contact also makes contact with said first load-transfer stationary contact, (5) then moving said tap-selector movable contacts from said second tapselector position to a third tap-selector position wherein said first tap-selector movable contact remains in contact with said second tap-selector stationary contact and said second tap-selector movable contact makes contact with a third tap-selector stationary contact adjacent to said second tap-selector stationary contact on the side of said second tap-selector stationary contact opposite to said first tap-selector stationary contact, and (6) then moving said loadransfer movable contacts from said fourth load-transfer position to said first load-transfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer Sta-- tionary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving member comprising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair or" pinions located in the plane of, and engageable with, said first Geneva gear.

16. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tap-selector stationary contacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given time either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-elector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the neXt adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tapselector movable contact; a second load-transfer stationary contact electrically connected to said second tapselector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said load-transfer stationary contact; and means for switching said load conductor means from electrical connection with first and second adjacent taps to electrical connection with said second tap and a third tap adjacent to said second tap on the side of said second tap opposite to said first tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said second load-transfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first loadtransfer movable contact remains in contact with said second load-transfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tap-selector movable contacts from a first tap-selector position wherein said first tap-selector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact with a second said tap-selector stationary contact, adjacent to said first tap-selector stationary contact, to a second tap-selector position wherein said second tap-selector movable contact remains in contact with said second tap-selector stationary contact and said first tap-selector movable contact also makes contact with said second tap-selector stationary contact, (3) then moving said load-transfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said second load-transfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; (4) then moving said load-transfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second load-transfer movable contact also makes contact with said first load-transfer stationary contact, (5) then moving said tap-selector movable contacts from said second tap-selector position to a third tap-selector position wherein said first tapselector movable contact remains in contact with said second tap-selector stationary contact and said second tap-selector movable contact makes contact with a third tap-selector stationary contact adjacent to said second tap-selector stationary contact on the side of said second tap-selector stationary contact opposite to said first tapselector stationary contact, and 6) then moving said loadtransfer movable contacts from said fourth load-transfer position to said first load-transfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear located in a plane parallel to the plane of said first Geneva gear and drivingly connected to said tap-selector movable contacts, and a Geneva driving mem ber, rotatable in both directions, comprising a pinion located in the plane of, and engageable with, said second Geneva gear and a pair of pinions spaced at an angle of less than and located in the plane of, and engageable with, said first Geneva gear.

17. In tap changing apparatus, tap selecting means comprising in combination: a plurality of tap-selector stationary contacts electrically connected respectively to a plurality of taps; first and second tap-selector movable contacts associated with said tapselector stationary con- 2.3 tacts; means for moving said tap-selector movable contacts into and out of contact with said tap-selector stationary contacts selectively to provide at a given tn'ne either electrical contact between both said tap-selector movable contacts and one said tap-selector stationary contact or between said first tap-selector movable contact and one said tap-selector stationary contact and between said second tap-selector movable contact and the next adjacent tap-selector stationary contact; a first load-transfer stationary contact electrically connected to said first tapselector movable contact; a second load-transfer stationary contact electrically connected to said second tap-selector movable contact; first and second load-transfer movable contacts associated with said load-transfer stationary contacts; load conductor means electrically connected to both said load-transfer movable contacts; means for moving said load-transfer movable contacts into and out of contact with said load-transfer stationary contacts selectively to provide at a given time physical and electrical contact either between both said load-transfer movable contacts and either said load-transfer stationary contact or between said first load-transfer movable contact and either said load-transfer stationary contact and between said second load-transfer movable contact and the other said loadtransfer stationary contact; and means for switching said load conductor means from electrical connection with first and second adjacent taps to electrical connection with said second tap and a third tap adjacent to said second tap on the side of said second tap opposite to said first tap comprising, means for (1) moving said load-transfer movable contacts from a first load-transfer position wherein said first load-transfer movable contact is in contact with said second load-transfer stationary contact and said second load-transfer movable contact is in contact with said first load-transfer stationary contact to a second load-transfer position wherein said first load-transfer movable contact remains in contact with said second loadtransfer stationary contact and said second load-transfer movable contact also makes contact with said second load-transfer stationary contact, (2) then moving said tapselector movable contacts from a first tap-selector position wherein said first tap-selector movable contact is in contact with a first said tap-selector stationary contact and said second tap-selector movable contact is in contact with a second said tap-selector stationary contact, adjacent to said first tap-selector stationary contact, to a second tap-selector position wherein said second tap-selector movable contact remains in contact with said second tapselector stationary contact and said first tap-selector movable contact also makes contact with said second tapselector stationary contact, (3) then moving said loadtransfer movable contacts from said second load-transfer position to a third load-transfer position wherein said second load-transfer movable contact remains in contact with said second load-transfer stationary contact and said first load-transfer movable contact makes contact with said first load-transfer stationary contact; (4) then moving said load-transfer movable contacts from said third load-transfer position to a fourth load-transfer position wherein said first load-transfer movable contact remains in contact with said first load-transfer stationary contact and said second load-transfer movable contact also makes contact with said first load-transfer stationary contact, (5) then moving said tap-selector movable contacts from said second tap-selector position to a third tapselector position wherein said first tap-selector movable contact remains in contact with said second tap-selector stationary contact and said second tap-selector movable contact makes contact with a third tap-selector stationary contact adjacent to said second tap-selector stationary contact on the side of said second tap-selector stationary contact opposite to said first tap-selector stationary contact, and (6) then moving said load-transfer movable contacts from said fourth load-transfer position to said first loadtransfer position wherein said second load-transfer movable contact remains in contact with said first load-transfer stationary contact and said first load-transfer movable contact makes contact with said second load-transfer stationary contact; said switching means including a first Geneva gear drivingly connected to said load-transfer movable contacts, a second Geneva gear drivingly connected to said tap-selector movable contacts, and 21 Geneva driving member, rotatable in both directions about an axis located between the axes of said first and second Geneva gears, comprising a first pinion located in the plane of, and engageable with, said second Geneva gear and second and third pinions spaced symmetrically on either side of said first pinion, each at an acute angle from said first pinion, and located in the plane of, and engageable with, said first Geneva gear.

References Cited in the file of this patent UNITED STATES PATENTS 

